Ring galaxies are very interesting objects. Their most prominent feature is the lack of a typical spiral structure, replaced by a narrow, ring-shaped accumulation of gas and stars. Such a peculiar distribution of matter is believed to form during collision of a spiral, gas-rich small galaxy with a early-type one . For small impact collision generates a ring-shaped structure in the disk in which the stellar and gaseous material crowd together. Large impact collision produce crescent-shaped rings with an off-centred remnant nucleus. In both cases the ring contains many massive, relatively young blue stars, which are extremely bright. The central region contains relatively little luminous matter.